Sun angle at noon on either March 21st or September 21st in Houston, Texas
The amount, direction, intensity and angle of sun all affect how your plants will grow. Here are several surefire ways to evaluate your sun to help determine what to plant where.
- Sun Angle
The range of sun angles during a growing season can help you determine which parts of a yard will get enough sun to support plants that need it and which parts will be in shade most of the time. Knowing how much ground will be in the shade during your growing season will let you know where to put plants that need full sun. For example, we planted tomatoes four feet north of our one story garage and they were in full sun all day long from early June to late August. Here are some sun angle ranges for a few cities:
The high end of the range is calculated at noon on the summer solstice, the low end of the range is calculated at noon on the winter solstice. You can use this solar calculator from Sustainable by Design to find information for where you live.
- Minneapolis: 68º - 22º
- Kansas City: 74º - 27º
- Houston: 82º - 37º
- Azimuth Angle
The azimuth of the sun determines how far north the sun will strike the east and west sides of a shaded area. (or how far south if you are in the southern hemisphere). The closer you live to the equator, the less this changes throughout the year. If you live closer to either pole, your shaded planting zone will grow and shrink throughout the year. In order to ensure that shaded plants don't get too much sun, keep them away from the far eastern or far western edges of a shade making object.
- Shade Making Obstacles
How close to the fence can your vegetable garden be before it will get too much shade? Is there enough room on the north side of the house to plant vegetables? Why aren't my tomatoes growing? Most of these questions can be answered by looking at shade making objects and moving the plantings. We like to plan our garden in February so we have enough time to get seedlings started before the ground thaws in Minneapolis. During that time the yard looks very different than it will in June because the sun angles are lower and none of the trees have leaves. Keep in mind where your deciduous trees are and how much shade buildings and trees will cast before planting in the spring.
MORE GARDEN PLANNING ON APARTMENT THERAPY:
Look! Sunset's Plant Finder Tool
(Images: Laurie McGinley)